Multiply.
-$( 7 + \sqrt { 7 } ) ^ { 2 }$
A) $49 + 14 \sqrt { 7 }$
B) $14 + 14 \sqrt { 7 }$
C) $56 + 7 \sqrt { 7 }$
D) $56 + 14 \sqrt { 7 }$

Name: Multiply. -$( 7 + \sqrt { 7 } ) ^ { 2 }$ A) $49 + 14 \sqrt { 7 }$ B) $14 + 14 \sqrt { 7 }$ C) $56 + 7 \sqrt { 7 }$ D) $56 + 14 \sqrt { 7 }$
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Question

Quizplus · Accepted Answer

Using the formula $(a+b)^2=a^2+2ab+b^2$, we have 
\begin{align*}
(7+\sqrt{7})^2 &= 7^2+2\cdot7\cdot\sqrt{7}+(\sqrt7)^2 \
&= 49+14\sqrt{7}+7 \
&= 56+14\sqrt{7}.
\end{align*}
Therefore, the answer is D.

Multiply - (7+7)2( 7 + \sqrt { 7 } ) ^ { 2 }(7+7​)2

Multiply
- $( 7 + \sqrt { 7 } ) ^ { 2 }$